The invention relates to cathode ray tubes (CRTs) and, more particularly, to a mounting lug for mounting the CRT to a cabinet.
Shown in FIG. 1 is a conventional cathode ray tube 10 (CRT) having an evacuated glass envelope 32 including a substantially rectangular faceplate panel 30 and a tubular neck 34 connected by a funnel 22. An electron gun (not shown) is mounted within the tubular neck 34 and is designed to be used with an external magnetic deflection yoke 42 positioned in the vicinity of the funnel-to-neck junction. The faceplate panel 30 has a peripheral flange or sidewall 12 that is sealed to the funnel 22 by a glass frit 38.
An implosion resistant band 14 surrounds at least a portion of the sidewall 12. One type of implosion resistant band 14 is a shrink fit band formed from a steel strip that is joined at the ends by a weld 36. Before assembly, the periphery of the implosion resistant band 14 is initially slightly smaller than the periphery of the faceplate panel 30. The implosion resistant band 14 is then heated to cause it to expand to a dimension that allows it to be fitted around the sidewall 12 of the faceplate panel 30. As the implosion resistant band 14 cools, it shrinks to contact the sidewall 12 thereby applying a compressive force to the faceplate panel 30. Although an implosion resistant band 14 in the form of a shrinkfit band is illustrated, alternatively, the implosion resistant band 14 may be a conventional tension band having ends fixed by a crimped closure.
Positioned at corners of the CRT 10 are mounting lugs 16 that affix the CRT 10 within a cabinet 18 adjacent to a substantially rectangular cabinet opening 46. As shown in FIG. 2, each of the mounting lugs 16 typically has a mounting portion 26 positioned essentially perpendicular to a base portion 28. The base portion 28 of the mounting lug 16 is attached to a surface 70 of the implosion resistant band 14 by a weld. The mounting lug 16 may optionally be integral with or disposed between the implosion resistant band 14 and the sidewall 12 of the faceplate panel 30. The mounting portion 26 of the mounting lug 16 is provided with an aperture 44 to effectively couple the CRT 10 to a corresponding hole 48 in the cabinet 18 with an attachment member 20 such as a bolt, screw, etc. Because the mounting portion 26 is essentially perpendicular to the sidewall 12 of the faceplate panel 30, the CRT 10 is coupled to the cabinet 18 along a Z-axis of the CRT 10. The Z-axis is shown by the dashed lines in FIGS. 1 and 2.
The cabinet 18 includes speakers 24, as best shown in FIG. 1. Because most speakers 24 are installed to point towards the viewer, the speakers 24 are mounted in the cabinet 18 parallel to the Z-axis of the CRT 10. Microphonic action associated with the speakers 24 creates vibrations in the cabinet 18. Because the speakers 18 and the mounting lugs 16 are both mounted in the cabinet 18 along the Z-axis, vibrations along the Z-axis are coupled through the cabinet 18 to the mounting lugs 16 and finally to the CRT 10. Such microphonic vibration coupling to the CRT 10 can cause undesirable anomalies in the picture due to electron beam misregister or component shifting within the CRT 10. It is therefore desirable to develop a mounting lug 16 that will couple a CRT 10 to a cabinet along an axis other than parallel to the Z-axis to minimize microphonic vibration coupling to the CRT 10.
This invention relates to a cathode ray tube (CRT) having an evacuated envelope including a substantially rectangular faceplate panel with a sidewall joined to a funnel and an implosion resistant band surrounding at least a portion of the sidewall in contact therewith. The CRT is mounted in a cabinet by a plurality of mounting lugs. The mounting lugs include a base portion attached to the implosion resistant band, an adjoining portion substantially perpendicular to the base portion, and a mounting portion positioned at an angle in respect to the adjoining portion. The mounting portion has an aperture for receiving a fastner for coupling the mounting portion to the cabinet.